Submarines of the First submarine group proceeded to the northern pacific and to the
coast of Alaska to carry out reconnaissance missions :

the I 25 was off Kodiak by 24 May. I 19 was near Dutch Harbor by 28 may
I 15 was off the central Aleutians and I 17 was off the western Aleutians.
These submarines remained on their respective stations until operation AL
was concluded, then they started to shift their patrol areas towards the
west coast of the US.

On 5 june a japanese recon plane spotted a drifting US carrier 150 miles north northeast
of Midway.
The I 168 commanded by Yahachi Tanabe was ordered to go and sink her. It had bombed Midway on the 4th
and later Eastern Island as well. Sighting an american carrier nearly dead
in the water on 6 June, Tanabe calmly manoevered his boat to the best firing position
and , at 1305, almost abeam of the dammaged carrier and at a range of a
1000 yards, launched four torpedoes.
Tanabe heard four explosions before the US destroyers started a series of
very heavy depth charges attacks for about seven hours.Eventually obliged to
surfaced Tanabe spotted the DDs some distance away and was able to escape
on the surface under the cover of dusk.

after the conclusion of operation AL , 5 coean cruising subs shifted patrol stations to
the waters of the west coast of America in much the same manner as did their
predecessors.
They were relieved in mid-june by seven old ocean cruising subs of the 2nd sub group.
The I 25 sank one cargo vessel on 20 June and briefley bombraded Astoria, Oregon on the 21st.
The I 7 also sank an enemy vessel before the end of the patrol in mid-July.
Captain Tomejiro Tamaki recommended the deployment of many submarines against enemy lines of communications
in areas of dense Shipping. However his recommendations went mostly unheeded, these surveillance
operations were not undertaken systematically, thus becoming mere nuisance patrols.

submarine patrols in the India Ocean and the southeast coast of Australia mid-1942

IO and Australia :

Submarines of Unit A and the Eastern Unit continued to patrol their respective areas after the special
attacks on Sidney harbor.

The results were considerable.

The I boats of unit A operated mainly in the Mozambique Channel and off the eastern coast of Madagascar until mid-July.

The I 10 sank 8 cargo ships !
The I 16 sank four, the I 18 sank 3, and the I 20 sank 7 cargo vessels of various sizes.

At the same time two japanese armed merchant cruisers (Aikoku maru 10437 tons and Hokoku maru 10438 tons were operating
in the central and western parts of the IO.

Japanese submarines in the Australian waters were also reasonably successful at this time.Five submarines
of the Eastern Unit patrolled off the New South Wales coast.

I 21 sank 3 cargo vessels and bombarded Newcastle on 8 June. I 24 and I 27 each sank one ship, I 29 dammaged a similar vessel.
However, australian records suggest that japanese caused more dammage than official japanese accounts seem to claim :
ships attacked by japanese submarines between 16 May and 3 August totaled eight.

Thirty cargo vessels were sunk (150 000 tons !), two captured, and many dammaged, was not without significance, however,
the mounting pressure of war, especially with the coming struggle for Guadalcanal, would not permit the submarine forces to
continue operations aimed mainly at the destruction of enemy shipping.

The Navy was shocked with the news of the american landing on 7 August 1942.Admiral Mikawa soon launched counter-attacks ,
the battle for Savo Island , 9 August 1942.

Yamamoto ordered all available forces, including submarines, to concentrate around Guadalcanal, Yamamoto himself moved to Truk in the Battleship Yamato.

Six submarines of the third submarine group and five of the seventh group had been operating in the south pacific in July but
not all of them could respond straight away : some were in need of repairs or resupply. There were also nine submarines of the First group under his command.

With the exception of ten submarines of the Eight submarine group based at Penang and in the Indian Ocean, the majority of operational ocean-cruising and fleet type submarines were concentrated in the Pacific in the final months of 1942 in waters of the eastern Solomon for the struggle for Guadalcanal.

Surprisingly, the first submarines deployed failed to interfere with the allied landings.
The battle for the eastern Solomon took place 24 August 1942. The submarines in ppicket line A, southeast of San Cristobal, failed to detect
the american carriers.
A new line was established later between Santa Cruz Island in the east and San Cristobal Island in the west. This picket line held promises.

At dawn on 31 August Commander Yokota of the I-26 spotted an american carrier well east of San Cristobal Island and launched six torpedoes
with a 120 angle on bow and a 3800 yards range. One torpedo hit, the I 26 was unable to confirm the effects of the attack at the time
because of 4 hours of heavy ASW attacks.

US carriers were a favored prey for japanese submarines in the eastern Solomon. On the afternoon of 13 September, japanese planes sighted an american carrier 200 miles southeast of San Cristobal Island.

Carrier Wasp fell prey to Commander Takaichi Kinashi in I-19, stationed near the center of the picket line, about 140 miles southeast of San Cristobal Island.
At noon on the 15th he heard several propeller sounds, 50 minutes later he sighted a carrier, a cruiser, and escorting destroyers at a distance of 8 miles.

On two occasions the carrier changed course on the inside, thus receding the range while also presenting a more favorable angle on bow.

Finally, at 1345, the I-19 fired six torpedoes at the carrier target, with a 50 degrees angle on bow and a range of a 1000 yards.
Three of I-19's type 95 torpedoes hit the Wasp, and three other approached another carrier group built around the Hornet (CV-8) some eight miles
away.
One torpedo hit the battleship USS North Carolina, another hit the Destroyer O'Brien causing the ship later to break in two, the sixth ran along without hitting anything.

COmmander Kinashi's attack was one of the most successful of the war. Although an element of chance favored Kinashi's hits on the North Carolina and teh O'Brien, this remarkable salvo offers ample evidence of the superiority of japanese torpedoes.

Submarine operations in September, October untill the evacuation of Guadalcanal

September :

Pressure was increased on submarine operations to prevent US reinforcements from reaching Guadalcanal.
All submarines were placed under the command of Read Adm. Shigeaki Yamakazi, commander of squadron 1. However,
japanese submarine interference with the buildup on the island remained marginal.

October :

The struggle became more intense. The battleship Kongo and Haruna bombarded Henderson field at midnight on the 13th destroying some 48 of the 90 US aircraft there. The Japanese planned a total attack on the 22nd, then postponed it to the 25th. Carrier task forces from both sides clashed from the 19th till the 26th in the battle of Santa Cruz.

I-15, I-21 and I-24 sighted the US forces steaming south from Santa Cruz at a point 200 miles west of Espiritu Santo. They fired torpedoes, but no hits were scored against the fast moving targets.

The IJN fleet was larger than the american and so was its margin of victory :

Carrier Hornet sunkCarrier Enterprise dammaged.

Carrier Shokaku and light carrierZuiho dammaged.

At sea the role of the submarines decame more important because of the dammage both carrier groups sustained, the boats (I15, I17, I19, I26 and I4, I5, I7, I8, I22 and I176) were to patrol around Guadalcanal.

On 13 November, during the Third Battle of the Solomon Sea (American: Naval Battle of Guadalcanal), she also hit the badly-damaged cruiser USS Juneau (CL-52) at 10°33′S 161°03′E﻿ / ﻿-10.55, 161.05.

I-26’s torpedo set off Juneau’s magazine, blowing the ship in half; only ten of the ship's 650-man crew were ultimately rescued, not including the five Sullivan brothers.[5]

On the night of 25–26 October 1944, in the aftermath of the Battle off Samar, I-26 attacked USS Petrof Bay (CVE-80) off Leyte. I-26 was sunk by either USS Coolbaugh (DE-217) or USS Richard M. Rowell (DE-403).

Since most subs needed overhauls in early 1943, only 3 of them carried out offensive missions in the IO in early 1943 (I-27, I-37 and I-29) sinking eight ships.

Eight ocean-cruising submarines of the Eight submarine group were not assigned to Guadalcanal. Operations against commerce held the mot potential in the Indian Ocean where merchant shipping was rarely escorted.
In january 1943, the Navy began distributing a new publication called 'Strategic reference for the destruction of maritime traffic by submarine" but it was not wholeheartedly followed...

mid 1943 :

compared to operations in the south pacific, operations in the Indian Ocean, the Arabian Sea and the Bay of Bengal remained lucrative in mid 1943. One reason was that submarines were deployed against merchant ships and supply lines rather than specifically against combat vessels.
Sixteen vessels were sunk and five dammaged between July and December 1943.
I-26 landed indian revolutionnaries near Karachi in the Arabian sea for insurgency in India.

21 november 1943 : news of success against Tarawa, and against Makin in the Gilberts, was shocking to the japanese high command.
Circunmstances did not allow the deployment of regular navy forces, submarines from truk and Kwajalein were tasked with attacking US forces.

There were only nine submarines available : I-19, I-21,I-35, I-39, I-40, I-169, I-174, I-175 and RO-38.
due to constant picket line shifting, six of the original nine were sunk...

On 23 November, the Japanese submarine I-175 arrived off Makin. The temporary task group built around Rear Admiral H.M. Mullinnix's three escorts, Liscome Bay, USS Coral Sea and USS Corregidor commanded by Rear Admiral Robert M. Griffin in USS New Mexico was steaming 20 miles southwest of Butaritari Island at 15 knots.

There was no warning of a submarine in the area until about 0510 when a lookout shouted: "Here comes a torpedo!" The torpedo struck abaft of the after engine room and hit the aircraft bomb stockpile, causing a major explosion engulfing the entire vessel and sending shrapnel out 5,000 yards.

USS Liscorme Bay

Due to the heavy casualties suffered by the IJN submarines, the operation was halted 4 December 1943.

Only the I-8 commanded by commander Shinji Uchino successfully completed the treacherous journey. She left Penang on 6 July 1943 with quinine and an extra crew of 48 sailors as the germans were to give the U 1224 to the japanese. She went round the cape of Good Hope, and crossed the equator on 2 AUgust. The ship had a weird twin deck-gun and rendez-voused with U-161 near the Azores.

She arrived at Brest 61 days after leaving Penang. She left again on 5 October and arrived 5 December in Singapore then sailed to Kure where she arrived 21 December.

I 29 did the same trip leaving SIngapore on December 16th 1943 arriving at Lorient March 10th 1944. She left France 16 April and arrived at Singapore on 14 July. She was then ambushed by 3 US subs and sunk by 3 torpedoes from USS Sawfish.

I-52 was the last to attempt such a voyage. She sortied from Singapore on 23 April 1944. It was sunk in mid-June by aircrafts from USS Bogue (CVE-9) on 24 JUne 1944.

U-1224 was a German submarine Type 1XC/40. Served as RO 501 in Japanese service from 15 Feb, 1944. Sunk 13 May, 1944 in the mid-Atlantic north-west of Cape Verde Islands, in position 18.08N, 33.13W, by depth charges from the US destroyer escort USS Francis M. Robinson. Her crew had arrived safely in France with I-8 the previous year.